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How to remove a bad execution plan from SQL Server?
Look to improve query performance and understand what is causing the execution plan changes. Never use the DBCC command FREEPROCCACHE without the content inside the parentheses, especially in production environments, as this will remove ALL execution plans from SQL Server plan cache.
What does execution plan look like in SQL Server?
(The query is generated by entity framework and executed using sp_executesql) The execution plan during the poor performance period looked like this: Some background on the data- running the query above would never return more than 400 rows.
What happens when you restart a SQL Server?
This is what happens when you restart SQL Server. Correct term will SQL Server has to create new execution plans, choose the ‘reasonably good one’ and save it in the cache to reuse. or instead, SQL will need to create new execution plans library in order to keep on improving the executions?
Do you have to create new execution plans?
Correct term will SQL Server has to create new execution plans, choose the ‘reasonably good one’ and save it in the cache to reuse. or instead, SQL will need to create new execution plans library in order to keep on improving the executions?
How to blow away a stored execution plan?
Or if it’s a stored procedure, you can use the sp_recompile procedure against the stored procedure to blow away the plan. (Thanks @DBArgenis for this tip!) Run a version of the query that puts the plan you want to be in cache.
When do I need to change my execution plan?
This will automatically happen when approximately 20% of the rows in the table have been modified (the algorithm is more complicated, but 20% is pretty easy to remember). Updated statistics will cause the optimizer to consider a new execution plan for your query.
What to look for in SQL execution plan?
There are number of general signs in the SQL Execution Plan that indicate potentially bad performance spots on the query. For example, the most expensive operator that has the highest cost, related to the overall query cost, is a good starting point for the query performance troubleshooting.